Organic polysulfides such as alkyltrisulfides are useful for many purposes such as additive for elastomers, as antioxidants for lubricating oils, as intermediate for the production of organic chemicals, insecticides, and germicides and as additive to diesel fuels to improve the cetane number and ignition qualities of these fuels. These compounds are also useful in the compounding of extreme pressure lubricants and in the acceleration of rubber treating processes.
Such polysulfide compounds can be produced by reacting mercaptans with elemental sulfur in the presence of a basic catalyst. For example, Shaw (U.S. Pat. No. 5,530,163) discloses that organic polysulfides can be produced from a mercaptan and sulfur catalyzed by a basic catalyst.
A conventional process for producing an organic polysulfide is to react a mercaptan with elemental sulfur. However, the polysulfide thus produced is generally associated with some unreacted mercaptans and dissolved H.sub.2 S, both of which contribute to unpleasant odor. Additionally, possibly because of the unreacted mercaptan and/or the catalyst, the polysulfide thus produced generally becomes unstable, i.e., the polysulfide turns cloudy, upon storage. The mercaptan content can also increase with storage. The instability and odor greatly reduce the desirability and utility of organic polysulfides.
Therefore, there is an increasing need to develop a process for producing a substantially odor-reduced and substantially a stable organic polysulfide.